Alex Rickabaugh 5be186035f feat(ivy): enable inheritance of factory functions in definitions (#25392)
This commit creates an API for factory functions which allows them
to be inherited from one another. To do so, it differentiates between
the factory function as a wrapper for a constructor and the factory
function in ngInjectableDefs which is determined by a default
provider.

The new form is:

factory: (t?) => new (t || SomeType)(inject(Dep1), inject(Dep2))

The 't' parameter allows for constructor inheritance. A subclass with
no declared constructor inherits its constructor from the superclass.
With the 't' parameter, a subclass can call the superclass' factory
function and use it to create an instance of the subclass.

For @Injectables with configured providers, the factory function is
of the form:

factory: (t?) => t ? constructorInject(t) : provider();

where constructorInject(t) creates an instance of 't' using the
naturally declared constructor of the type, and where provider()
creates an instance of the base type using the special declared
provider on @Injectable.

PR Close #25392
2018-08-09 09:58:13 -07:00

75 lines
3.1 KiB
TypeScript

/**
* @license
* Copyright Google Inc. All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import {CompileReflector} from '../compile_reflector';
import {ConstantPool} from '../constant_pool';
import * as o from '../output/output_ast';
import {jitStatements} from '../output/output_jit';
/**
* Implementation of `CompileReflector` which resolves references to @angular/core
* symbols at runtime, according to a consumer-provided mapping.
*
* Only supports `resolveExternalReference`, all other methods throw.
*/
class R3JitReflector implements CompileReflector {
constructor(private context: {[key: string]: any}) {}
resolveExternalReference(ref: o.ExternalReference): any {
// This reflector only handles @angular/core imports.
if (ref.moduleName !== '@angular/core') {
throw new Error(
`Cannot resolve external reference to ${ref.moduleName}, only references to @angular/core are supported.`);
}
if (!this.context.hasOwnProperty(ref.name !)) {
throw new Error(`No value provided for @angular/core symbol '${ref.name!}'.`);
}
return this.context[ref.name !];
}
parameters(typeOrFunc: any): any[][] { throw new Error('Not implemented.'); }
annotations(typeOrFunc: any): any[] { throw new Error('Not implemented.'); }
shallowAnnotations(typeOrFunc: any): any[] { throw new Error('Not implemented.'); }
tryAnnotations(typeOrFunc: any): any[] { throw new Error('Not implemented.'); }
propMetadata(typeOrFunc: any): {[key: string]: any[];} { throw new Error('Not implemented.'); }
hasLifecycleHook(type: any, lcProperty: string): boolean { throw new Error('Not implemented.'); }
guards(typeOrFunc: any): {[key: string]: any;} { throw new Error('Not implemented.'); }
componentModuleUrl(type: any, cmpMetadata: any): string { throw new Error('Not implemented.'); }
}
/**
* JIT compiles an expression and returns the result of executing that expression.
*
* @param def the definition which will be compiled and executed to get the value to patch
* @param context an object map of @angular/core symbol names to symbols which will be available in
* the context of the compiled expression
* @param sourceUrl a URL to use for the source map of the compiled expression
* @param constantPool an optional `ConstantPool` which contains constants used in the expression
*/
export function jitExpression(
def: o.Expression, context: {[key: string]: any}, sourceUrl: string,
preStatements: o.Statement[]): any {
// The ConstantPool may contain Statements which declare variables used in the final expression.
// Therefore, its statements need to precede the actual JIT operation. The final statement is a
// declaration of $def which is set to the expression being compiled.
const statements: o.Statement[] = [
...preStatements,
new o.DeclareVarStmt('$def', def, undefined, [o.StmtModifier.Exported]),
];
const res = jitStatements(sourceUrl, statements, new R3JitReflector(context), false);
return res['$def'];
}